This invention relates to suspension systems for land vehicles, and more particularly to suspension systems for wheeled vehicles such as railway vehicles, i.e., railway locomotives and railway cars, tractors, trailers, etc.
The invention is especially concerned with a suspension system for any wheeled vehicle which may travel over uneven surfaces, e.g., railway vehicles which may travel over uneven track, tractors, or similar vehicles which may travel over uneven terrain, etc. In travelling over uneven surfaces, wheeled vehicles may be caused to rock or sway from side to side, often to the extent that the vehicle overturns. Railway vehicles may derail. The rocking or swaying is a problem not only because it may make the ride uncomfortable for riders of the vehicle, or may cause shifting of cargo and damage thereto, or even overturn the vehicle, but also because extra propulsive power is required to overcome the unevenness of the surface (e.g., track or terrain) over which the vehicle is travelling, thus wasting energy. Also, it imposes increased strain on the vehicle and may require design of the vehicle with oversized components to take the increased strain, thus increasing the cost of building the vehicle.